1/* 2 * Handling of different ABIs (personalities). 3 * 4 * We group personalities into execution domains which have their 5 * own handlers for kernel entry points, signal mapping, etc... 6 * 7 * 2001-05-06 Complete rewrite, Christoph Hellwig (hch@infradead.org) 8 */ 9 10#include <linux/init.h> 11#include <linux/kernel.h> 12#include <linux/kmod.h> 13#include <linux/module.h> 14#include <linux/personality.h> 15#include <linux/proc_fs.h> 16#include <linux/sched.h> 17#include <linux/seq_file.h> 18#include <linux/syscalls.h> 19#include <linux/sysctl.h> 20#include <linux/types.h> 21#include <linux/fs_struct.h> 22 23 24static void default_handler(int, struct pt_regs *); 25 26static struct exec_domain *exec_domains = &default_exec_domain; 27static DEFINE_RWLOCK(exec_domains_lock); 28 29 30static unsigned long ident_map[32] = { 31 0, 1, 2, 3, 4, 5, 6, 7, 32 8, 9, 10, 11, 12, 13, 14, 15, 33 16, 17, 18, 19, 20, 21, 22, 23, 34 24, 25, 26, 27, 28, 29, 30, 31 35}; 36 37struct exec_domain default_exec_domain = { 38 .name = "Linux", /* name */ 39 .handler = default_handler, /* lcall7 causes a seg fault. */ 40 .pers_low = 0, /* PER_LINUX personality. */ 41 .pers_high = 0, /* PER_LINUX personality. */ 42 .signal_map = ident_map, /* Identity map signals. */ 43 .signal_invmap = ident_map, /* - both ways. */ 44}; 45 46 47static void 48default_handler(int segment, struct pt_regs *regp) 49{ 50 set_personality(0); 51 52 if (current_thread_info()->exec_domain->handler != default_handler) 53 current_thread_info()->exec_domain->handler(segment, regp); 54 else 55 send_sig(SIGSEGV, current, 1); 56} 57 58static struct exec_domain * 59lookup_exec_domain(unsigned int personality) 60{ 61 unsigned int pers = personality(personality); 62 struct exec_domain *ep; 63 64 read_lock(&exec_domains_lock); 65 for (ep = exec_domains; ep; ep = ep->next) { 66 if (pers >= ep->pers_low && pers <= ep->pers_high) 67 if (try_module_get(ep->module)) 68 goto out; 69 } 70 71#ifdef CONFIG_MODULES 72 read_unlock(&exec_domains_lock); 73 request_module("personality-%d", pers); 74 read_lock(&exec_domains_lock); 75 76 for (ep = exec_domains; ep; ep = ep->next) { 77 if (pers >= ep->pers_low && pers <= ep->pers_high) 78 if (try_module_get(ep->module)) 79 goto out; 80 } 81#endif 82 83 ep = &default_exec_domain; 84out: 85 read_unlock(&exec_domains_lock); 86 return (ep); 87} 88 89int 90register_exec_domain(struct exec_domain *ep) 91{ 92 struct exec_domain *tmp; 93 int err = -EBUSY; 94 95 if (ep == NULL) 96 return -EINVAL; 97 98 if (ep->next != NULL) 99 return -EBUSY; 100 101 write_lock(&exec_domains_lock); 102 for (tmp = exec_domains; tmp; tmp = tmp->next) { 103 if (tmp == ep) 104 goto out; 105 } 106 107 ep->next = exec_domains; 108 exec_domains = ep; 109 err = 0; 110 111out: 112 write_unlock(&exec_domains_lock); 113 return (err); 114} 115 116int 117unregister_exec_domain(struct exec_domain *ep) 118{ 119 struct exec_domain **epp; 120 121 epp = &exec_domains; 122 write_lock(&exec_domains_lock); 123 for (epp = &exec_domains; *epp; epp = &(*epp)->next) { 124 if (ep == *epp) 125 goto unregister; 126 } 127 write_unlock(&exec_domains_lock); 128 return -EINVAL; 129 130unregister: 131 *epp = ep->next; 132 ep->next = NULL; 133 write_unlock(&exec_domains_lock); 134 return 0; 135} 136 137int __set_personality(unsigned int personality) 138{ 139 struct exec_domain *oep = current_thread_info()->exec_domain; 140 141 current_thread_info()->exec_domain = lookup_exec_domain(personality); 142 current->personality = personality; 143 module_put(oep->module); 144 145 return 0; 146} 147 148#ifdef CONFIG_PROC_FS 149static int execdomains_proc_show(struct seq_file *m, void *v) 150{ 151 struct exec_domain *ep; 152 153 read_lock(&exec_domains_lock); 154 for (ep = exec_domains; ep; ep = ep->next) 155 seq_printf(m, "%d-%d\t%-16s\t[%s]\n", 156 ep->pers_low, ep->pers_high, ep->name, 157 module_name(ep->module)); 158 read_unlock(&exec_domains_lock); 159 return 0; 160} 161 162static int execdomains_proc_open(struct inode *inode, struct file *file) 163{ 164 return single_open(file, execdomains_proc_show, NULL); 165} 166 167static const struct file_operations execdomains_proc_fops = { 168 .open = execdomains_proc_open, 169 .read = seq_read, 170 .llseek = seq_lseek, 171 .release = single_release, 172}; 173 174static int __init proc_execdomains_init(void) 175{ 176 proc_create("execdomains", 0, NULL, &execdomains_proc_fops); 177 return 0; 178} 179module_init(proc_execdomains_init); 180#endif 181 182SYSCALL_DEFINE1(personality, unsigned int, personality) 183{ 184 unsigned int old = current->personality; 185 186 if (personality != 0xffffffff) 187 set_personality(personality); 188 189 return old; 190} 191 192 193EXPORT_SYMBOL(register_exec_domain); 194EXPORT_SYMBOL(unregister_exec_domain); 195EXPORT_SYMBOL(__set_personality); 196